This is a feature that most Nikon cameras have and even some of the newer Canons. I'm excited to try some portraits with this technique. Go into your shooting menu and select multiple exposure.
You can play with these settings, but in the D7000 I seemed to get the best results from leaving the auto gain ON.
Select done and the top of the camera LCD should look like this.
Now you are ready to experiment! The camera will take three images and blend them together!
This was just a quick test to check how many exposures I could make in one frame. Shooting portraits with textures would be the next experiment for me! Have fun!